"It's complicated."

Cell phones are kinda weird because they carry some of the elements that were built up around hardline phones (similar to how physical mail has a ton of protections that accumulated historically that make it distinct from other mediums).

This one generally gets treated legally more like any other data collection in a public space. Essentially, it's not a violation of your rights if somebody sits on a street corner and takes a picture of every car that drives by. There's a really interesting debate about whether there should be some concept of scale (Flock makes it really easy to effectively put somebody on every street corner), but the law generally hasn't changed to take that kind of thing into consideration.

You can see the same kind of thing in many of the AI training debates. Training AIs on bulk data has been found in a couple different cases to not be copyright infringement because they're drawing parallels to any other learning, even if the scale here is obviously several orders of magnitude apart from what was ever possible before.

For what it's worth: if I own a business in the US and have a camera pointed at the street, and the police ask me for footage, I don't need to require a subpoena. I can just choose to give it to them.

The law doesn't need to change. Court opinions just need to emerge (hasn't been tested yet), and this is quite clearly angling in the direction of the cell tower data decision.

> For what it's worth: if I own a business in the US and have a camera pointed at the street, and the police ask me for footage, I don't need to require a subpoena. I can just choose to give it to them.

Correct, and SCOTUS decided this was inappropriate for cell tower data because 1) you effectively need a cell phone to live in the modern world, and 2) having a cell phone spits of tons of data.

This is directly analogous to Flock. It's more likely than not that this will end up getting a Third Party Doctrine exception (i.e. Flock and similar will be forbidden from providing this data to the government in lieu of a subpoena)

> Essentially, it's not a violation of your rights if somebody sits on a street corner and takes a picture of every car that drives by.

In theory sure. But the strange truth is that in practice you aren't allowed to do this.